Writing Ordinal Numbers: First, 1st, and When to Use Each

Last updated 24 August 2026

An ordinal names a position rather than a quantity: not three but third, not forty-two but forty-second. Written English has two forms — the word and the figure-plus-suffix — and they are not interchangeable in every context.

Building the word

Most ordinals are the cardinal plus -th: four → fourth, six → sixth, ten → tenth, seventeen → seventeenth. A handful are irregular and simply have to be known:

Two more patterns are worth naming. Tens ending in -y change to -ieth: twenty → twentieth, forty → fortieth, ninety → ninetieth. And the scale words take plain -th: hundredth, thousandth, millionth, billionth.

Compound ordinals

This is where most errors happen. In a compound number, only the final element becomes an ordinal, and the hyphenation is unchanged from the cardinal:

• twenty-one → twenty-first
• forty-two → forty-second
• ninety-nine → ninety-ninth
• one hundred twenty-one → one hundred twenty-first
• one thousand one hundred forty-two → one thousand one hundred forty-second

The wrong instinct is to treat the whole compound as a unit and suffix it: forty-twoth, twenty-oneth. Those are not forms. Note also that one hundredth and one hundred first are different numbers — the first is 100th, the second is 101st.

Figures with suffixes

The short form is the figure plus the last two letters of the written ordinal: 1st, 2nd, 3rd, 4th. Three points:

1. The suffix follows the last digit, so it depends on the number’s ending: 21st, 22nd, 23rd, 24th. The teens are the exception — 11th, 12th and 13th all take -th despite ending in 1, 2 and 3.
2. No capitals, no superscript. Write 1st, not 1ST or 1ˢᵗ. Word processors often superscript automatically; most style guides ask you to turn that off, and screen readers handle the plain form better.
3. No apostrophe. The 1990s, not the 1990’s, and the 3rd, not the 3rd’.

Which form when

• Spell out ordinals in running prose, especially low ones: the third attempt, her twenty-first birthday.
• Use figures in dates, addresses, numbered lists, rankings and anywhere the number is data rather than prose: 3rd Avenue, finished 42nd.
• Centuries go either way but should be consistent: the 21st century and the twenty-first century are both standard.

Dates

British convention writes the day before the month and often drops the suffix entirely in formal writing: 1 May 2026. American convention puts the month first: May 1, 2026. The spelled-out ordinal — the first of May — is normal in speech and in formal invitations, and unusual elsewhere. Whichever you choose, avoid all-numeric dates in international documents: 05/01/2026 means two different days depending on the reader.

Ordinals that are not numbers

A few position words do the job of an ordinal without looking like one. Last, final, next and penultimate all mark position in a sequence, and they cannot be combined with an ordinal: the last third means the final third of something, not the third item. Latter and former order exactly two items and are wrong for three or more — with three, use first, second and third rather than stretching latter to cover the end of the list.

There is also a small set of Latin-derived forms still used in formal and legal writing: primary, secondary, tertiary, and the quinquennial / centenary family for anniversaries. They are ordinals in meaning but take no suffix, and mixing them with -th forms in one list reads badly.

Plurals and ranges

Ordinals pluralise regularly — the first three finishers, in their twenties — but note that the twenties is a decade, not a set of twentieth places. Ranges take the ordinal only once at each end: the 1st to 5th of June, or more naturally 1–5 June. Repeating the suffix inside a numeric range (1st–5th) is acceptable but heavier than it needs to be.

Related

• Cardinal vs ordinal numbers sets the two side by side.
• Hyphens in numbers covers the hyphen the ordinal inherits.
• Every number page prints both the cardinal and the ordinal — see 21 in words — or use the converter.